SUSAN SARANDON - film actress, Oscar winner, bona-fide Hollywood royalty. Over the course of her long acting career, the 60-year-old has been many people and many things - from a witch seeking revenge to the downtrodden Arkansas waitress Louise Sawyer who made a stand for modern day female emancipation in the blockbuster Thelma and Louise.

She has become latterly known, in her native America, for her political activism, hounding President George W Bush and engaging in a long-running battle with New York's former mayor Rudolph Giuliani, almost as much as for her acting career.

She is also a mother - her partner is actor and director Tim Robbins - who has managed to keep her children away from the damaging glare of publicity and the excesses of an A-lister lifestyle.

But one thing has eluded Sarandon for the last 60 years - laying a legitimate claim to her suspected Welsh ancestry.

She has always believed, and cherished the idea, that she is descended from Welsh stock, that her distant relatives carved out a living in the sweeping hills of the breathtaking Welsh landscape, long before her great-grandparents emigrated to the land of hope and freedom in the late 19th century.

'There's something about Wales that has always sounded so romantic and mysterious,' she said in her almost lazy New York drawl.

'In my family it was rumoured that on my dad's side we were English, Irish and Welsh. You get these stories that you kind of like to hold on to because you like the sound of them.

'Of course, when I started acting, all these very interesting actors were Welsh, and it just sounds like a very kinda explosive background.

'I was very happy to think that I was part Welsh, but I know so little that I'm open to anything.'

If you Google Susan Sarandon and Welsh, there are more than 40,000 sites proclaiming, and seeming to confirm, her Celtic roots. But while she, her nine brothers and sisters, and the rest of the internet community appear to share the belief that the family originated in the land of my fathers, until now, there has been no concrete proof, only family rumours passed down like heirlooms.

Sarandon's search for evidence of her Welsh roots is the subject of the latest BBC Wales mini-series Coming Home, which followed her, and her party of nine relatives, including 14-year-old son Miles, as they zigzagged across Wales and England trying to pinpoint that elusive ancestry.

It was a journey which also embraced some of the bleakest years of our recent social history, crime, illegitimacy and Wales' not insignificant role in industrialising the globe.

Sarandon was born Susan Abigail Tomalin, a surname which is derived from the common Welsh name Thomas.

Her father Philip Leslie Tomalin was, it is believed, of Irish, Welsh and English ancestry, while her mother, Lenora Marie Criscione, was born in Sicily.

While the Tomalin surname may be a pretty big clue to the fact that someone in her family tree once lived in Wales, the genealogy is not as simple - while the name can be traced back to Carmarthenshire in 1280, her own family tree only goes as far back as Thomas Tomalin, who was born in 1701, and came from Luton, in Bedfordshire.

Later generations of the farming Tomalins all lived and worked in south east England.

It was in the 1870s, when William Tomalin - the actress's great- grandfather - was living in Islington and working as a common labourer, that Sarandon's family tree began to get interesting, albeit complex, although there was still not the slightest hint of a Welsh connection.

William Tomalin met and married Susanna Beams before he emigrated to New York - his wife, a servant in London's grand Portman Square, would follow him some years later, earning her the nickname 'Spunky Susanna', from Sarandon.

It was the Guyatt side of the family tree - James Beams and Sophia Guyatt were Sarandon's great-great grandparents - which eventually yielded a link between Wales and the Oscar-winning actress, although the family of labourers largely lived and worked in Wiltshire.

In the inauspicious surroundings of St James' church, in Ludgershall, on the eastern tip of Salisbury Plain, midway through Sarandon's week-long trip to Wales, the Guyatt family tree came to life.

Among the many Guyatt children born in the midst of one of England's great agricultural depressions, were brothers Charles and John.

At the age of 17, Charles was found guilty of poaching a wild rabbit, with a net and ferret, and was given a six- month sentence. After his imprisonment the two brothers moved to Bridgend where they worked as general labourers at the Tondu ironworks, probably as a means of escaping the abject poverty of the countryside.

'Now we have our Welsh connection to Wales,' said a delighted Sarandon. 'Now I see - through crime we got to Wales. Excellent.'

Tondu ironworks, which was opened in 1838, made railway lines which were then exported around the world.

Local historian Keith Strange said, 'There was a terrible depression in rural England, there was near famine. People had the choice of either going to London to try to make their fortune or to come to the nearest big industrial centre, which was South Wales, and find work.

'Work was readily available and relatively well-paid compared to some - this was definitely a better life.

'But in moving to a place like this, they were contributing to the depression in rural England.

'It was brought about in the 1870s by a series of bad harvests, but Britain had coped with that before. But cheap American grain had started to flood into Britain and that had come from the prairies on railway lines made in places like this (Tondu).

'It was Welsh railway lines that enabled cheap American corn to get to New York and ports like Boston and across, and that's what really slammed agriculture and why families like (Sarandon's) would have moved to a place like this.'

Sarandon's direct bloodline comes from Charles Guyatt, but despite the Tondu connection, he never settled in Wales as he soon moved to the Ukraine to work for the Welsh-owned Hughesovska Ironworks, along with hundreds more from South Wales who were lured by the higher wages.

It appears that the family eventually emigrated to New York.

Despite this tantalising familial connection to Wales, it was not enough to establish Sarandon's or the Tomalins' legitimate claim to the Welsh roots they so desperately wanted.

And so the family turned to the latest weapon in ancestry - science and to Oxford University, which has been building a database of DNA samples from every corner in the UK and can be used to pinpoint the geographic origins of a bloodline.

A sample of Sarandon's DNA, taken at the start of her seven-day odyssey, was analysed in a bid to trace her mother's bloodline back through history.

But far from being conclusive proof of a Welsh connection, however, it revealed that the female line originated in the Dordogne region of France.

Dr Brian Sykes, one of the UK's top geneticists at Oxford University, told Sarandon, 'This particular piece of DNA is something that you got from your mother and we can trace a direct line way, way back into the past, hundreds, thousands and tens of thousands of years.

'We found that you are a descendant of a woman that I have given the name Helena, who was one of seven clan mothers, who lived in the Dordogne in South France 20,000 years ago.

'If you are looking for a Welsh link, I don't think, based on these results, that you will find it in your mother's mother's mother's line. There may be parts of your DNA that have come from Wales, but I can't find it in that particular line - it's more continental than Celtic.'

The clan of Helena is the largest and most successful of the seven native clans, with 41% of Europeans belonging to one of its many branches.

It began 20,000 years ago with the birth of Helena somewhere in the valleys of the Dordogne and the Vezere, in south central France. The clan is widespread throughout all parts of Europe, but reaches its highest frequency among the Basque people of northern Spain and southern France.

Sarandon's brother Terry volunteered to also give a DNA sample to determine whether the paternal line, traced back through the Y chromosome, would solve the Welsh question once and for all.

The DNA samples take three days to process and are compared against the same database. Like maternal genealogies, men also tend to cluster into a small number of groups - there are a total of 18, including five clans in native Europeans.

Terry's DNA was traced back to one of these clans, and was then compared with other DNA samples taken from other people in Britain to see whether there was a geographical link.

Dr Sykes found 25 others with an exact Y chromosome match, all of whom were living in Mid and North Wales, proving, categorically that early generations of the Tomalin family came from Wales and confirming Sarandon's long-cherished belief that she has Welsh ancestry.

Terry added, 'Does that mean that I get tickets for the Six Nations next year?'

Coming Home: Susan Sarandon will be broadcast on BBC One Wales on Wednesday at 7.30pm